Avian influenza viruses of the H6 subtype are prevalent in wild ducks and likely play an important role in the ecology of influenza viruses through reassortment with other avian influenza viruses. Yet, only 152 Vietnamese H6 virus sequences were available in GISAID (Global Initiative on Sharing All Influenza Data) prior to this study with the most recent sequences being from 2018. Through surveillance in Vietnamese live bird markets from 2018 to 2021, we identified 287 samples containing one or several H6 viruses and other influenza A virus subtypes, demonstrating a high rate of co-infections among birds in Vietnamese live bird markets. For the 132 H6 samples with unique influenza virus sequences, we conducted phylogenetic and genetic analyses. Most of the H6 viruses were similar to each other and closely related to other H6 viruses; however, signs of reassortment with other avian influenza viruses were evident. At the genetic level, the Vietnamese H6 viruses characterized in our study encode a single basic amino acid at the HA cleavage site, consistent with low pathogenicity in poultry. The Vietnamese H6 viruses analyzed here possess an amino acid motif in HA that confers binding to both avian- and human-type receptors on host cells, consistent with their ability to infect mammals. The frequent detection of H6 viruses in Vietnamese live bird markets, the high rate of co-infections of birds with different influenza viruses, and the dual receptor-binding specificity of these viruses warrant their close monitoring for potential infection and spread among mammals.
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http://dx.doi.org/10.3390/v16030367 | DOI Listing |
Sci Immunol
January 2025
Ragon Institute of Mass General, MIT, and Harvard, Cambridge, MA 02139, USA.
Understanding the naïve B cell repertoire and its specificity for potential zoonotic threats, such as the highly pathogenic avian influenza (HPAI) H5Nx viruses, may allow prediction of infection- or vaccine-specific responses. However, this naïve repertoire and the possibility to respond to emerging, prepandemic viruses are largely undetermined. Here, we profiled naïve B cell reactivity against a prototypical HPAI H5 hemagglutinin (HA), the major target of antibody responses.
View Article and Find Full Text PDFVaccines (Basel)
January 2025
Department of Comparative Pathobiology, Purdue Institute of Inflammation, Immunology and Infectious Disease, College of Veterinary Medicine, Purdue University, 625 Harrison St., West Lafayette, IN 47907, USA.
An effective universal influenza vaccine is urgently needed to overcome the limitations of current seasonal influenza vaccines, which are ineffective against mismatched strains and unable to protect against pandemic influenza. In this study, bovine and human adenoviral vector-based vaccine platforms were utilized to express various combinations of antigens. These included the H5N1 hemagglutinin (HA) stem region or HA2, the extracellular domain of matrix protein 2 of influenza A virus, HA signal peptide (SP), trimerization domain, excretory peptide, and the autophagy-inducing peptide C5 (AIP-C5).
View Article and Find Full Text PDFVaccines (Basel)
January 2025
Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
Background/objectives: In preparation for a potential pandemic caused by the H5N1 highly pathogenic avian influenza (HPAI) virus, pre-pandemic vaccines against several viral clades have been developed and stocked worldwide. Although these vaccines are well tolerated, their immunogenicity and cross-reactivity with viruses of different clades can be improved.
Methods: To address this aspect, we generated recombinant influenza vaccines against H5-subtype viruses using two different strains of highly attenuated vaccinia virus (VACV) vectors.
Vaccines (Basel)
January 2025
College of Veterinary Medicine, Institute of Comparative Medicine, Yangzhou University, Yangzhou 225009, China.
Background: The current H3N2 influenza subunit vaccine exhibits weak immunogenicity, which limits its effectiveness in preventing and controlling influenza virus infections.
Methods: In this study, we aimed to develop a T4 phage-based nanovaccine designed to enhance the immunogenicity of two antigens by displaying the HA1 and M2e antigens of the H3N2 influenza virus on each phage nanoparticle. Specifically, we fused the Soc protein with the HA1 antigen and the Hoc protein with the M2e antigen, assembling them onto a T4 phage that lacks Soc and Hoc proteins (SocHocT4), thereby constructing a nanovaccine that concurrently presents both HA1 and M2e antigens.
Vaccines (Basel)
January 2025
Smorodintsev Research Institute of Influenza, The Ministry of Health of the Russian Federation, Saint-Petersburg 197022, Russia.
Background: Influenza viruses with truncated NS1 proteins show promise as viral vectors and candidates for mucosal universal influenza vaccines. These mutant NS1 viruses, which lack the N-terminal half of the NS1 protein (124 a.a.
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